Two-sectioned back-pressured catalytic converter

ABSTRACT

A two-sectioned back-pressured catalytic converter has a main body, a tail tube, and a honeycomb carrier. The honeycomb carrier is mounted securely in the main body and has a first section relatively proximal to the intake opening and a second section relatively proximal to the exhaust opening. The density of the holes of the first section is higher than that of the second section. Therefore, waste gas has sufficient space for expansion when passing through the first section, and thus the pressure and the temperature are both lowered, solving problems of the back pressure and the backward pushing. The tail tube is securely mounted into the main body to form a baffle. The waste gas will hit the baffle after passing the honeycomb carrier and generate turbulence which can slow down the gas and make the gas fully react with the precious metal coating.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a catalytic converter of an exhaustpipe of an internal combustion engine, especially to a catalyticconverter for vehicles.

2. Description of the Prior Arts

A catalytic converter is a device mounted in an exhaust pipe, adoptsprecious metal coating such as Platinum, Palladium, and Rhodium ascatalyst, and reduces the toxic gas by catalytic mechanism. In order tofully convert the toxic gas, the prior arts generally use a honeycombcarrier to increase the surface area to complete the reaction.

Conventionally, a catalytic converter is combined with a main body andthe honeycomb carrier. The main body is a hollow tube that may be in anyshape, and the honeycomb carrier is mounted in the main body. Thesection of the honeycomb carrier is a high-density grid structure, andthe aforementioned precious metal coating is deposited on the walls ofthe holes of the honeycomb carrier.

A density of the holes of the aforementioned honeycomb carrier isconstant everywhere in each hole, and is generally from 1000 to 1200cpsi (Cells per Square Inch). Such a high-density structure has thefollowing disadvantages.

First, the toxic gas is passing the honeycomb carrier slowly due to thehigh density of the holes while the engine is still discharging so thata back pressure may be generated and even push back the gas. Then theturbine blades will be broken because of the high temperature created bythe increasing pressure which is the result of the slow flowing speed ofthe gas.

Second, the aforementioned back pressure will decrease the dischargeefficiency and affect the power output of the engine at a low speedwhile the engine is still working at a high speed.

To overcome the shortcomings, the present invention provides atwo-sectioned back-pressured catalytic converter to mitigate or obviatethe aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide atwo-sectioned back-pressured catalytic converter that can reduce thepressure and the temperature of the carrier so that the turbine bladeswill not be broken due to the high temperature and the dischargeefficiency will be improved.

The two-sectioned back-pressured catalytic converter comprises a mainbody, a tail tube, and a honeycomb carrier. The main body is hollow andhas an intake opening and an exhaust opening. The tail tube is securelymounted in the exhaust opening of the main body and is mounted into themain body to form a baffle in the main body. The honeycomb carrier ismounted securely in the main body, and has a first section and a secondsection which are connected to each other. The first section is disposedproximal to the intake opening relative to the second section, and thesecond section is disposed proximal to the exhaust opening relative tothe first section. The first section and the second section respectivelyhave multiple holes. A density of the holes of the first section ishigher than a density of the holes of the second section.

The honeycomb carrier has the first section and the second section ofdifferent densities, and the density of the holes of the first sectionis higher than the density of the holes of the second section. Thus, thewaste gas has sufficient space for expansion with the pressure beingreduced, thereby solving the problems of the back pressure and thepushing back gas and releasing the pressure accumulated in the firstsection. In addition, the baffle formed by the tail tube which ismounted into the main body creates turbulence when the toxic gas passingthrough the second section so that the toxic gas can stay in the secondsection longer to be fully converted.

Other objectives, advantages and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a first embodiment of a two-sectionedback-pressured catalytic converter in accordance with the presentinvention;

FIG. 2 is a side view in partial section of the two-sectionedback-pressured catalytic converter in FIG. 1;

FIG. 3 is a front view in partial section of a honeycomb carrier of thetwo-sectioned back-pressured catalytic converter in FIG. 1;

FIG. 4 is a side view in partial section of the two-sectionedback-pressured catalytic converter in FIG. 1, showing a flow of wastegas; and

FIG. 5 is a side view of a second embodiment of a two-sectionedback-pressured catalytic converter in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a two-sectioned back-pressuredcatalytic converter in accordance with the present invention comprises amain body 10, a honeycomb carrier 20, a connecting tube 30, and a tailtube 40.

The main body 10 is hollow and has an intake opening and an exhaustopening. In a preferred embodiment, the main body 10 further comprisesan expanding section 11, a carrier section 12, and a tapered section 13which are sequentially connected to one another. An opening of theexpanding section 11 is said intake opening, and an inner diameter ofthe expanding section 11 progressively increases from the intake openingto the carrier section 12. An opening of the tapered section 13 is saidexhaust opening, and an inner diameter of the tapered section 13progressively decreases from the carrier section 12 to the exhaustopening. But an inner diameter of the main body 10 is not limited to theabove mentioned, as the main body 10 can be implemented without theexpanding section 11 and the tapered section 13, and the inner diameterof the main body 10 is of the same size from the intake opening to theexhaust opening.

The honeycomb carrier 20 is mounted securely on an inner wall of themain body 10. Specifically, the honeycomb carrier 20 is mounted securelyon an inner wall of the carrier section 12 of the main body 10. Thehoneycomb carrier 20 comprises a first section 21 and a second section22 which are connected to each other. The first section 21 is disposedproximal to the intake opening relative to the second section 22, andthe second section 22 is disposed proximal to the exhaust openingrelative to the first section 21. With reference to FIGS. 2 and 3, thefirst section 21 and the second section 22 respectively have multipleholes 211, 221, and a density of the holes 211 of the first section 21is higher than a density of the holes 221 of the second section 22.

In a preferred embodiment, the density of the holes 211 of the firstsection 21 is from 100 to 150 cpsi, preferably 100 cpsi. The density ofthe holes 221 of the second section 22 is from 60 to 100 cpsi,preferably 60 cpsi. But the densities of the holes 211, 221 are notlimited to the abovementioned ranges and values.

In addition, in a preferred embodiment, a length of the first section 21of the honeycomb carrier 20 is preferably, but not limited to, shorterthan a length of the second section 22. Alternatively, the length of thefirst section 21 and the length of the second section 22 can also beequal or the length of the first section 21 is longer than the length ofthe second section 22.

In addition, a precious metal coating as the catalyst for reducing toxicgas is deposited on inner walls of the holes 211 of the first section 21and also on inner walls of the holes 221 of the second section 22. In apreferred embodiment, the precious metal coating is made of, but notlimited to, Platinum, Palladium, or Rhodium. Besides, a total surfacearea of the holes 211, 221 in the present invention is smaller than atotal surface area of a conventional honeycomb carrier because of thedensity of the holes 211 of the first section 21 and the density of theholes 221 of the second section 22 are smaller than the density of theconventional honeycomb carrier. Thus, a concentration of the preciousmetal coating on the walls of the holes 211, 221 is higher in order toachieve the same catalytic efficiency of the conventional honeycombcarrier.

The connecting tube 30 is connected to an exhaust opening of an engineand communicates with the intake opening of the main body 10.Specifically, the connecting tube 30 is securely mounted into theexpanding section 11, but it is not limited thereto, as the connectingtube 30 and the expanding section 11 can also be connected by butt-jointor by any other means. In addition, a mounting hole 31 is formed througha wall of the connecting tube 30 in order to be mounted with an oxygensensor.

The tail tube 40 is mounted securely into the exhaust opening of themain body 10 and communicates with an exterior environment.Specifically, the tail tube 40 is securely mounted into the taperedsection 13 of the main body 10. Because an inner diameter of the taperedsection 13 is bigger than an outer diameter of the tail tube 40, thepart of the tail tube 40 that is mounted into the tapered section 13forms a baffle 42. In addition, a mounting hole 41 is formed through awall of the tail tube 40 in order to be mounted with an oxygen sensor.Besides, with reference to FIG. 1, in a preferred embodiment, the tailtube 40 is preferably, but not limited to, a straight tube. In thesecond embodiment with reference to FIG. 5, the tail tube 40A can alsobe an upward curved tube.

For use, the present invention is mounted in the middle or the end partof the exhaust pipe. With reference to FIG. 4, when the engine isworking, the toxic gas flows into the main body 10 from the connectingtube 30, and then enters the first section 21 to be converted for thefirst time after passing through the expanding section 11 of the mainbody 10. Because the density of the holes 211 is higher and the diameterof the holes 211 is smaller, the flowing speed of the gas is slow in thefirst section 21. After passing through the first section 21, the gasenters the second section 22, wherein the diameter of the holes isbigger to have the second conversion. This time the flowing speed of thegas is faster compared with the flowing speed of the first conversionthat takes place in the first section 21. After the gas has passedthrough the second section 22, the gas that is relatively near the innerwall of the main body 10 flows along the inner wall of the taperedsection 13 and end up hitting the baffle 42 which is formed by the partof the tail tube 40 that is mounted into the tapered section 13, andthen turbulence is generated nearby the baffle 42. The turbulence willslow down the flow of the gas and then the gas will stay in the secondsection 22 longer to extend the time for the gas to be converted. Afterall this, the gas passes through the tail tube 40 and is discharged tothe exterior environment. In addition, even if the main body 10 has notapered section 13 and the inner diameter of the main body 10 is of afixed size, the gas will still flow along the inner wall of the mainbody 10 and end up hitting the baffle 42 and generating the turbulence.

When the present invention is in use, the waste gas which has beenconverted and passed through the first section 21 enters the secondsection 22 which has the relatively bigger diameter of the holes. Thebigger holes let the waste gas release the pressure and increase theflowing speed in order to achieve the purpose of reducing the backpressure, increasing the discharge efficiency in a low speed, andavoiding the turbine blades from being broken by the high temperature.In addition, the density of the holes of the present invention is lowerthan the density of the holes of the prior arts so that the presentinvention can reduce the pressure much more efficiently.

Even though numerous characteristics and advantages of the presentinvention have been set forth in the foregoing description, togetherwith details of the structure and features of the invention, thedisclosure is illustrative only. Changes may be made in the details,especially in matters of shape, size, and arrangement of parts withinthe principles of the invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed.

What is claimed is:
 1. A two-sectioned back-pressured catalyticconverter comprising: a main body being hollow, and having an intakeopening; and an exhaust opening; a tail tube securely mounted in theexhaust opening of the main body and mounted into the main body to forma baffle in the main body; and a honeycomb carrier mounted securely inthe main body, and having a first section and a second section which areconnected to each other; the first section disposed proximal to theintake opening relative to the second section, and the second sectiondisposed proximal to the exhaust opening relative to the first section;the first section and the second section respectively having multipleholes, a density of the holes of the first section is higher than adensity of the holes of the second section.
 2. The two-sectionedback-pressured catalytic converter as claimed in claim 1, wherein alength of the first section is shorter than a length of the secondsection.
 3. The two-sectioned back-pressured catalytic converter asclaimed in claim 1, wherein the density of the holes of the firstsection is from 100 to 150 cpsi.
 4. The two-sectioned back-pressuredcatalytic converter as claimed in claim 2, wherein the density of theholes of the first section is from 100 to 150 cpsi.
 5. The two-sectionedback-pressured catalytic converter as claimed in claim 3, wherein thedensity of the holes of the first section is 100 cpsi.
 6. Thetwo-sectioned back-pressured catalytic converter as claimed in claim 4,wherein the density of the holes of the first section is 100 cpsi. 7.The two-sectioned back-pressured catalytic converter as claimed in claim1, wherein the density of the holes of the second section is from 60 to100 cpsi.
 8. The two-sectioned back-pressured catalytic converter asclaimed in claim 6, wherein the density of the holes of the secondsection is from 60 to 100 cpsi.
 9. The two-sectioned back-pressuredcatalytic converter as claimed in claim 7, wherein the density of theholes of the second section is 60 cpsi.
 10. The two-sectionedback-pressured catalytic converter as claimed in claim 8, wherein thedensity of the holes of the second section is 60 cpsi.
 11. Thetwo-sectioned back-pressured catalytic converter as claimed in claim 1,wherein the main body has a carrier section, the honeycomb carriermounted in the carrier section; and a tapered section connected to thecarrier section, the exhaust opening formed on the tapered section, andthe tail tube mounted into the tapered section; wherein an innerdiameter of the tapered section progressively decreases from the carriersection to the exhaust opening.
 12. The two-sectioned back-pressuredcatalytic converter as claimed in claim 10, wherein the main body has acarrier section, the honeycomb carrier mounted in the carrier section;and a tapered section connected to the carrier section, the exhaustopening formed on the tapered section; and the tail tube mounted intothe tapered section; wherein an inner diameter of the tapered sectionprogressively decreases from the carrier section to the exhaust opening.